It has been discovered that tapered spray holes which have a diametrical cross-section that reduces in size from the inside surface of the nozzle body to the outside surface of the nozzle body, such as that described in EP 0 352 926, are prone to the formation of deposits within the hole which reduce its diameter and change its flow characteristics. The main problem with the formation of deposits is that the maximum flow rate through the spray hole is reduced and this is detrimental to the performance of the engine into which the injector is installed. Consequently, it is desired to have an improved design which prevents any reduction in the flow rate.